A city Department of Education worker may lose both his legs after a truck knocked a concrete barrier onto him outside an aviation-school annex at Kennedy Airport on Monday, officials said.

The freak accident occurred around 1:15 p.m. as DOE contract manager Mark Drake, 47, of Maspeth, Queens, was standing alongside the barrier in a parking lot in front of the Q-750 Aviation HS Annex, said police sources and education officials.

A driver backing up a truck nearby apparently failed to see either the barrier or Drake. His vehicle struck the barrier, which then toppled onto Drake and crushed his legs, a source said.

“He is in surgery right now at Jamaica Hospital, and he may lose his legs below the knee,” said Board of Education spokeswoman Margie Feinberg.

She said another DOE contract manager, Mohamed Meerza, was standing with Drake at the time and suffered bruises to the back of his legs.